Mass transfer and dispersion processes in connected conductivity structures : simulation, visualization, delineation and application
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2006
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| Online Access: | http://hdl.handle.net/1721.1/29584 |
| _version_ | 1811093832107819008 |
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| author | Zinn, Brendan Anderson, 1977- |
| author2 | Charles F. Harvey. |
| author_facet | Charles F. Harvey. Zinn, Brendan Anderson, 1977- |
| author_sort | Zinn, Brendan Anderson, 1977- |
| collection | MIT |
| description | Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003. |
| first_indexed | 2024-09-23T15:51:02Z |
| format | Thesis |
| id | mit-1721.1/29584 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T15:51:02Z |
| publishDate | 2006 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/295842019-04-11T00:55:58Z Mass transfer and dispersion processes in connected conductivity structures : simulation, visualization, delineation and application Zinn, Brendan Anderson, 1977- Charles F. Harvey. Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering. Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering. Civil and Environmental Engineering. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003. Includes bibliographical references (p. 161-167). This thesis focuses on mass transfer behavior, i.e., tailing, in solute transport, and on hydraulic conductivity heterogeneity. Macrodispersive theory, generally used to incorporate heterogeneity into solute transport, does not account for this tailing and makes assumptions about the structural characteristics of the heterogeneity, specifically that the field is multivariate gaussian. We move away from the multigaussian assumption to focus on the concept of connected pathways of high or low conductivity. We first motivate the importance of connected extreme conductivity values through the numerical creation of two-dimensional conductivity fields with nearly identical univariate conductivity distributions and covariances, but with varying connectedness of extreme values. We simulated flow and transport through these fields, using a particle tracking approach that incorporates advection and diffusion. We demonstrate that connectedness impacts flow by influencing the effective conductivity of the field, and connected high conductivity fields with relatively high variance displayed mass transfer behavior, driven by both advective and diffusive processes. We then conducted laboratory experiments to study three flow situations demonstrated by the first part of the work - classic dispersion, diffusion-driven mass transfer, and advection-driven mass transfer. By simultaneously measuring outflow concentration and the spatial distribution of solute in the tank, we demonstrate different breakthrough characteristics driven by different small-scale processes. Outflow concentrations match excellently with established models in the case of diffusive mass transfer and dispersion, and relatively well with a model we developed for the advective mass transfer scenario. (cont.) We generalized the experimental results by creating connected binary conductivity fields, delineating the conditions of connectedness and conductivity contrast that drive the various transport. Finally, we examine the implications of our earlier work, particularly the interplay between advection and diffusion in mass transfer. The presence of both processes creates late-time concentrations that are complex, but partially dependant on hydraulic gradients. We apply this to a hypothetical scenario of a pump-and-treat remediation - the existence of advective mass transfer creates situations in which solute mobilization can be sped up by pumping rate choices, and the complex interaction between mass transfer processes leads to more complex pumping rate decisions. by Brendan Anderson Zinn. Ph.D. 2006-03-24T16:04:46Z 2006-03-24T16:04:46Z 2003 2003 Thesis http://hdl.handle.net/1721.1/29584 52872563 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 167 p. 7595380 bytes 7595188 bytes application/pdf application/pdf application/pdf Massachusetts Institute of Technology |
| spellingShingle | Civil and Environmental Engineering. Zinn, Brendan Anderson, 1977- Mass transfer and dispersion processes in connected conductivity structures : simulation, visualization, delineation and application |
| title | Mass transfer and dispersion processes in connected conductivity structures : simulation, visualization, delineation and application |
| title_full | Mass transfer and dispersion processes in connected conductivity structures : simulation, visualization, delineation and application |
| title_fullStr | Mass transfer and dispersion processes in connected conductivity structures : simulation, visualization, delineation and application |
| title_full_unstemmed | Mass transfer and dispersion processes in connected conductivity structures : simulation, visualization, delineation and application |
| title_short | Mass transfer and dispersion processes in connected conductivity structures : simulation, visualization, delineation and application |
| title_sort | mass transfer and dispersion processes in connected conductivity structures simulation visualization delineation and application |
| topic | Civil and Environmental Engineering. |
| url | http://hdl.handle.net/1721.1/29584 |
| work_keys_str_mv | AT zinnbrendananderson1977 masstransferanddispersionprocessesinconnectedconductivitystructuressimulationvisualizationdelineationandapplication |